Improvement in aooing-machines



M. M. CRAM. ADD-1N G-MACHINES.

Patented Aug. 7,1877.

' luf# FIC-LIB N.FETERS, PHOTO-LITNOGRAPHER, WASHINGTON. D C4 V,ing play up and tween the supports b. One end of the yoke UNITED STATES PATENT OEEIGE.

MARSHALL M. CRAM, OF MANKATO, MlNNESOTA.

IMPROVEMENT IN ADDING-MACHlNES.

Specification forming part of Letters Patent No. [93,853, dated August 7,1877; application iiled April 19, 1877.

To all whom it may concern:

Be it known that I, MARSHALL M. CRAM, of Mankato, in the county of Blue Earth and State of Minnesota, have invented a new and useful Improvement in Adding-Machines, of which the following is a specication:

In the accompanying drawings, Figure 1 is a plan view; and Fig. 2 is aperspective view, part of the digit-keys being removed.

A represents a hanged ratchet-wheel, on the flange of which are one hundred teeth, c a. The hub a extends on one side, and is screw-threaded on the exterior. The wheel is secured to the shaft B, which is supported by two standards, b b, cut, with the baseplate C, from one piece of sheet metal, and bent up, and a quarter-twist given, as shown. The standard c, with slotted indicator-scale c', is also of the same piece as the base-plate. The arm D has a screw-threaded socket, d', and screws on the hub of the wheel. The pointer or index d, carried by the arm, moves in the slotted indicator-scale. The periphery of the wheel A is divided into spaces indicating units and tens, and numbered corresponding to the one hundred teeth.

Eis a yoke, through both, ends of which the shaft B passes, and the yoke has swingdown, the ends being beis extended beyond the shaft, as shown at e, and has attached a spiral spring, f, the other end of which is fastened to the base-plate. The upright k is secured to the base-plate, and has the top end bent over to serve as a stop for the yoke, the latter being held up to the stop by the spring f, acting on the extended end e. The yoke carries a ratchetpawl, t', in such position as to engage the teeth on the wheel. k is a rectangular lever, pivoted to the base-plate, and has under the part l a spring, which keeps the catch on the upper end of lever engaged with the teeth of the Wheel. This catch also forms alug, which serves to release the pawli when the partlof the lever, immediately below the number-one key, is depressed.

The numbers 1, 2, 3, VAL, 5, 6, 7, 8, and 9 are digit keys, each of which is pivoted or swung on the shaft, and, resting in front on the yoke E, have stop ends w 00 w bent downward, the stop of each key being of such length that when a key is pressed down until the stop end strikes the base-plate the wheel turns forward in the direction of the arrow a number of units corresponding to the number ofthe key.

H represents a crank, which, when the pawl and lever-catch are disengaged, is used for the purpose of turning the wheel back until the pin n on the wheel strikes against the pointer-arm D, by reason of the latter moving inward by the reverse rotation of the screw-threaded hub. The base-plate C is secured to a board, or may be fastened to a table.

My adding-machine operates in the following manner: The figures on the slotted indicator-scale o indicate hundreds, and those on the periphery of the wheel just above the indicator are units. The operator works the keys with his right hand, the thumb being used on key No. 9. To add a column of iigures, a key corresponding to each figure is pressed down as far as it will go, and allowed to rise again before pressing another. After pressing keys to correspond with all the numbers, the sum is read oif from the indicator, as shown by the pointer d, and from the wheel just above the indicator. It' another column is to be added, set down the righ t-hand figure, the others being to carry then, pressing the lever l, turn back the wheel by means of the crank H, as far as it will go, when the pointer will be at 0 on the indicator, and 0 will show on the wheel. Then count first what there was to carry, and proceed with the nexl column:

Having described my invention, I ela-ini and desire to secure by Letters Patent- 1. The anged ratchet-wheel A, having oi its periphery numbered spaces indicating unit s and tens, with the hub ai' extended on on side and screw-threaded exteriorly, the arni E D, with screw-threaded socket d', and carryin the pointer d, substantiallyas shown.

2. The base-plate C, standards b, and stanr ard c, with indicator-scale c', all cut from ou piece of sheet metal.

3. The pawl yi, attached to the yoke E, rec angular lever 7c, pivoted to the base-platt and having a spring under the part Z, and

the yoke, the keys hawing;

downward-extending stop ends of variable length, the said parts operating in connection With the ratchet-wheel A, as shown and described.

M. M. CRAM.

Witnesses H. K. LEE,

HENRY TOURTELOTTE. 

